Additive manufacturing of metallic components – Process, structure and properties

This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

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Metal Additive Manufacturing: A Review

Additive manufacturing of metals

A study of the microstructural evolution during selective laser melting of Ti–6Al–4V

Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power laser have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following a...

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Review of selective laser melting : materials and applications

https://cyberleninka.org/article/n/443668.pdf

Microstructure and mechanical properties of Selective Laser Melted 18Ni-300 steel

During selective laser melting, the irradiated material experiences large temperature fluctuations in a short time which causes unwanted thermal stresses. In order to assess thermal stresses in a simple and fast way, a new pragmatic method is developed, namely the bridge curvature method. The bridge curvature method is used to assess and qualitatively compare the influence of different laser scan patterns, laser parameter settings and more fundamental process changes on residual stresses. The results from the experiments, as well as the findings from literature, lead to two general conclusions: changes that reduce the high temperature gradient, like using short scan vectors and preheating of the base plate, reduce the thermal stresses. And, thermal stresses in a particular direction can be reduced by optimal choice of the orientation of scan vectors. The experiments indicate the reliability of the bridge curvature method. Statistical analysis is used to check the repeatability of the method and to quantif...

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Assessing and comparing influencing factors of residual stresses in selective laser melting using a novel analysis method

Microstructural investigation of Selective Laser Melting 316L stainless steel parts exposed to laser re-melting

Part and material properties in selective laser melting of metals

Purpose – Selective laser melting (SLM) is a powder metallurgical (PM) additive manufacturing process whereby a three‐dimensional part is built in a layer‐wise manner. During the process, a high intensity laser beam selectively scans a powder bed according to the computer‐aided design data of the part to be produced and the powder metal particles are completely molten. The process is capable of producing near full density (∼98‐99 per cent relative density) and functional metallic parts with a high geometrical freedom. However, insufficient surface quality of produced parts is one of the important limitations of the process. The purpose of this study is to apply laser re‐melting using a continuous wave laser during SLM production of 316L stainless steel and Ti6Al4V parts to overcome this limitation.Design/methodology/approach – After each layer is fully molten, the same slice data are used to re‐expose the layer for laser re‐melting. In this manner, laser re‐melting does not only improve the surface qualit...

Evren Yasa

Papers

Microstructure and mechanical properties of Selective Laser Melted 18Ni-300 steel

Assessing and comparing influencing factors of residual stresses in selective laser melting using a novel analysis method

Microstructural investigation of Selective Laser Melting 316L stainless steel parts exposed to laser re-melting

Part and material properties in selective laser melting of metals

The investigation of the influence of laser re‐melting on density, surface quality and microstructure of selective laser melting parts